Touch responsive static electric control



Feb. 28, R96? L. H. DIAMOND 3939799673 TOUCH RESPONSIVE STATIC ELECTRIC CONTROL Filed Jan. 7, 1965 R V1 o M T R N O E T D T mm A 4 M m G D 1 F H W M 6 E w/ 2 L K N Y 5 E B .L DION. 3 v mmm a LRi w a? M i Q m M .4 l M w M A W Aw 5 g E:

" United States Patent a ing second gas tube.

3,307,071 TOUCH RESPONSIVE STATIC ELECTRIC CONTROL Lew H. Diamond, Massapequa, N.Y., assignor to Otis Elevator Company, New York, N.Y., a corporation of New Jersey Filed Jan. 7, 1965, Ser. No. 423,907 4 Claims. (Cl. 315160) This invention relates to a control for an electric circuit.. It more particularly pertains to a control which is operable in response to the touch of a person and which, during its operation, is lighted to indicate its operated condition.

The first disclosures of touch responsive electric controls of the illuminating type appear in US. Patents Nos. 2,525,- 767 and 2,525,769 granted on October 17, 1950. These patents are directed to the employment of gas filled cold cathode tubes in touch responsive controls designed for use primarily in registering and storing calls for service in elevator systems. In these systems the touch of an intending passenger initiates the operation of such a control and causes its tube to conduct. The conduction of the tube registers the call for service by the intending passenger and the glow of the tube caused by its conduction provides an illuminated indication that the call is registered.

Frequently, in elevator systems, illuminated indications of the registration of calls are needed at a location remote from that of registration. In systems in which the gas tube arrangements of the heretofore mentioned patents are installed two methods are available for obtaining such remote indications. One of these methods uses the conduction of a gas tube in response to the touch of an intending passenger to operate a sensitive relay which engages a pair of its making contacts completing a circuit for lighting an incandescent lamp situated at the remote location. Of course, this method requires a sensitive relay and an incandescent lamp for each touch responsive control. The other method requires only a second gas filled tube for each touch responsive control and uses the conduction of each touch responsive tube to operate its correspond- The glow of the second tube thereby provides the illuminated indication desired. This latter method, however, requires that the wiring between each touch responsive tube and its corresponding second gas tube be shielded to prevent unwanted firings of the tubes by voltage impulses from other pieces of equipment.

Owing to the equipment needed with these forementioned methods it is evident that a more economical method of providing remote indications of the registration of calls is desirable.

Furthermore, since the introduction of illuminated touch responsive controls it has been the desire to provide a touch responsive control which is capable of being illurninated in any of various colors. With the gas tube type control, in which the color of the light radiated by the control is a function of the kind of gas in its tube, illumination in any of various colors is feasible only if the tube can be filled with a gas combination which radiates a white light from which undesirable colors can be filtered. Since such a combination has not as yet been discovered, a practical touch responsive control of the gas tube type capable of radiating light in any of various colors presently is not capable of production.

It is therefore an object of this invention to provide a control for an electric circuit which is touch responsive and which more economically permits the illuminated indication of a registered call at a location remote from that of registration.

It is another object of this invention to provide a Patented Feb. 28, 1967 control for an electric circuit which is touch responsive and which can be illuminated in any of various colors.

The invention employs a multi-terminal solid state device as a control for an electric circuit and involves controllably operating the device in response to persons touching a conducting button connected to one of its terminals.

In carrying out the invention in a presently preferred embodiment wherein it is used to eifect the registration of calls in an elevator system, a silicon controlled switch is provided in a suitable touch button fixture. The switch is arranged in the fixture so that its control gate extends near and is connected to a conducting button arranged in the fixture face plate. A source of direct current potential is across the anode cathode circuit of the switch and a source of alternating current potential is connected from the cathode circuit to ground. A resistance capacitance network connects the anode terminal to the anode gate terminal for reasons to be hereinafter described. When arranged in this manner the touch of a person to the conductive button causes the switch to conduct, registering the call and permitting the touch to be discontinued. An illuminated indication of the operation is effected by mounting an incandescent lamp behind the fixture face plate and connecting it in the cathode circuit between the cathode terminal and a direct current potential connection to the cathode circuit. Conduction by the switch causes current to flow through the lamp thereby illuminating it. An illuminated indication desired at any remote location is effected by connecting other such lamps in parallel with the aforementioned lamp.

Features and advantages of the invention will be apparent from the above statements and from the description and appended claims which follow.

In the drawing:

FIGURE 1 is a top view of that part of a single button control embodying the invention with parts in section;

FIGURE 2 is a side view of the single button control of FIGURE 1;

FIGURE 3 is a side view of certain parts of the single button control shown in FIGURE 1;

FIGURE 4 is a view taken along lines 4-4 of FIG- URE 3; and

FIGURE 5 is a simplified wiring diagram of the single button control.

Referring to FIGURES l, 2, 3 and 4, the single button control therein illustrated utilizes a silicon controlled switch 10 having a cathode 11, an anode 12, a control gate 13 and an anode gate 14. The switch is mounted on an insulated panel 15 which is enclosed in an outlet box (not shown) in any suitable manner. Also mounted on panel 15 are rheostat 16; condensers 20, 21 and 2-2; incandescent lamp 24; conductive wire 18 and terminal block 25. In the assembled fixture, panel 15 is set in insert slots 26 and 27 which are so located in sleeve 30' that lamp 24 is substantially concentric with the circular cross section of the sleeve. One end of sleeve 30 is closed by aperture cup-shaped cover 31 securely fitted therein. Cover 31 is made of light transmitting material, such as Lucite. It abuts face plate 32 which is formed with an aperture so as to permit transparent cup 33 to pass therethrough up to its lip 28. The body of cup 33 is seated in depression 34 of sleeve cover 31. A button 35 of conducting material and containing a threaded shank 35 is located in cup 33 to receive the touch of a person. Shank 36 passes through the apertures in plate 31 and cup 33 and in cooperation with nut 37 joins button 35, face plate 32, cup 33 and sleeve 30 in one unit. Shank 36 and nut 37 are so located that one of them makes electrical contact with conductive wire 18 mounted on panel 15.

Although some connecting wires are shown in FIG- URES 1 and 2, the electrical connections between components are more readily understandable from the simplified wiring diagram of FIGURE to which reference may now be had. A source of alternating current indicated by lines L1 and L2 feeds the primary of transformer 40, the secondary of which is in circuit with switch cathode 11. A direct current source, indicated by lines L3, L4 and L5, is applied to the anode and cathode circuits. The direct current potential connected between lines L3 and L4 maintains switch conducting after an operation has been initiated. The direct current source connected between lines L3 and L5 stops conduction of switch 10 when desired. One terminal of the secondary of transformer 40 is connected to ground 41, and the other is connected in series with incandescent lamp 24 in the cathode circuit. Line L4, the positive side of one direct current potential, is connected to switch anode 12. Line L5, the positive side of the other direct current potential, is connected to cathode 11 through line 45, knife switch 42, resistor 17 and condenser 23. Line L3, the common negative side of the direct current potentials, is connected to the junction at which the one terminal of the secondary of transformer 40 is connected to one terminal of incandescent lamp 24. The other terminal of incandescent lamp 24 is connected to cathode 11. Button 35 is connected through wire 18 and condenser 20 to the control gate 13. The anode gate 14 is connected to the anode 12 through a biasing means formed by parallel condenser 21 and rheostat 16. Condenser 22 is connected between control gate 13 and cathode 11.

In operation, upon a person touching button 35 a circuit is completed from the ground side of the secondary of transformer 40 through lamp 24, cathode 11, control gate 13, condenser 20, button 35 and back to ground by way of the persons body capacitance'to ground. This causes sufiicient current flow between the cathode 11 and the control gate 13 to cause the silicon controlled switch 10 to become conductive. Switch 10 remains conductive after the touch is removed because the direct current source connected between lines L3 and L4 causes a direct current to flow from line L4 through anode 12, cathode 11 and lamp 24 to line L3. Switch 10 can be restored to the non-conductive condition by canceling the voltage drop between its anode and cathode as by closing switch 42 to apply the potential of line L5 through the parallel circuits of condenser 23 and resistor 17. Switch 42 is reopened at the conclusion of the restoring operation if it is desired to permit switch 10 to become conductive the next time a person touches button 35.

It has been found satisfactory to employ a General Electric Company type 3N84 switch as switch 10 and to operate that switch with a 60 cycle alternating current potential of 200 volts R.M.S. across the secondary of transformer 40. Using a 28 volts G.E. type 757 lamp in the cathode circuit, direct current sources of 30 volts potential between L4 and L3 and 40 volts potential between lines L5 and L3 are satisfactory. A capacitance of 100 micromicrofarads has been found suitable for condenser 20. Such capacitance safeguards a person operating the control from any chance of electric shock while maintaining the sensitivity of the control at -a level which permits its operation by a person wearing gloves. Resistor 17 and condenser 23 prevent the 40 volt resetting potential connected between lines L5 and L3 from causing filament damage to lamp 24 but permit such potential to be applied to cathode 11 for a suflicient duration to restore switch 10 to the alt condition. For such purposes, condenser 23 may have a capacity of 5 microfarads and resistor 17 a resistance of 39,000 ohms.

In utilizing touch responsive controls to elfect the regis tration of calls in an elevator system it is desirable that they normally be sensitive enough to be operated by a person wearing gloves and yet be stable enough not to be operated by voltage transients in their alternating current power supply or by static charges in their environment.

With the prior art touch responsive controls the desirable sensitivity and stability were obtained by selecting tubes which operated within prescribed limits. With the herein described units stability is acquired by employing condensers 21 and 22, which may suitably be of 10,000 and 500 micromicrofarads capacity, respectively, to prevent unwanted operation by transient voltages. Sensitivity is controlled by placing resistance in parallel with-condenser 21. Rheostat 16 which may suitably have a maximum resistance of 100,000 ohms, is connected between anode 12 and anode gate 14 for this purpose. A rheostat is used to enable the resistance in parallel with condenser 21 to be adjusted in accordance with the sensitivity characteristics of the individual silicon controlled switches together with the conditions under which it s desired to have the controls operate. The following table shows various values of resistance desirable for two silicon control switches of the General Electric Company type 3N84 one highly sensitive and the other less sensitive operating under various conditions.

Highly sensitive silicon controlled switch Value of resistance between anode 12 Operating condition: and anode gate 5 Value of resistance between anode 12 Operating condition: and anode gate 14 Bare Finger ohms 2,300 Nylon Gloved Finger ohms 9,500

Pig Skin Leather Gloved Finger ohms 100,000

A remote indication of the registration of a call is provided by incandescent lamp 44 connected in parallel with lamp 24 as is illustrated in FIGURE 5. Light of any desired wavelength in the visible spectrum can be provided by the described control by use of filters intermediate the lamp and cup 33. Furthermore, the intensity of the light may be increased by utilizing a reflector to reflect the light from the lamp toward cup 33.

As many variations may be made without departing from the scope of the invention disclosed, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A control for electric circuits operable by the touch of a person and providing an illuminated indication of its operated condition comprising; a solid state semiconductive device having four terminals including an anode terminal, a cathode terminal, an anode gate terminal and a cathode gate terminal; a button of conductive material connected to said cathode gate terminal; a first current source connected between said anode terminal and said cathode terminal and applying a potential thereacross; a source of light located in proximity with said button and connected in series with said first current source and said device; means connected to said anode gate terminal for biasing said terminal with respect to the potential of said anode terminal; a periodic current source connected between ground and said cathode terminal, said periodic current source having suflicient potential magnitude to cause said semiconductive device to conduct between said cathode terminal and said cathode gate terminal when said button is touched by a person; said first current source having sufficient potential magnitude to cause said semiconductive device to conduct between its anode and cathode terminals when conduction occurs between its cathode and cathode gate terminals and to continue to conduct between said anode and cathode terminals after conducting ceases between said cathode and cathode gate terminals, the current flowing between said anode and cathode terminals when conduction occurs therebetween being sutficient to cause said light source to illuminate.

2. A control for electric circuits operable by the touch of a person and providing an illuminated indication of its operated condition comprising; a solid state semiconductive device having four terminals including an anode terminal, a cathode terminal, an anode gate terminal and a cathode gate terminal; a button of conductive material connected to said cathode gate terminal, said button being located in said control to permit it to be touched by a person; a source of light located in close proximity with said button and so oriented in said control that when illuminated its light is radiated in a direction to be perceived by a person touching said button; a first current source connected in series with and applying a potential across said source of light and the anode and cathode terminals of said device; a resistance capacitance network connected between said anode and anode gate terminals to bias said anode gate terminal with respect to the anode terminal; a capacitive element connected between said cathode and cathode gate terminals; a periodic current source connected between ground and said cathode terminal, said periodic current source having suflicient potential magnitude to cause said semiconductive device to conduct between said cathode and cathode gate terminals when said button is touched by a person; said first current source having suflicient potential magnitude to cause said semiconductive device to conduct between its anode and cathode terminals when conduction occurs between its cathode and cathode gate terminals and to continue to conduct between said anode and cathode terminals after conduction ceases between said cathode and cathode gate terminals, the current flowing between said anode and cathode terminals when conduction occurs therebetween being suflicient to cause said light source to illuminate.

3. A control for electric circuits operable by the touch of a person and providing an illuminated indication of its operation comprising; a silicon controlled switch having an anode, a cathode, a control gate and an anode gate; a light transmitting cover for said switch; a button of conductive material touchable by a person and electrically connected to the control gate terminal of said switch and located on said light transmitting cover; a miniature incandescent lamp having one terminal electrically connected to the cathode terminal of said switch; said lamp being mounted behind the light transmitting portion of said cover and extending toward said button; a parallel resistance capacitance filter network connected between the anode and the anode gate terminals of said switch; a direct current source connected between said anode terminal and the second terminal of said lamp; and an alternating current source connected between ground and the second terminal of said lamp having sufiicient potential magnitude to cause a current to flow between said control gate and said cathode terminals when said button is touched by a person; said direct current source being of sufficient potential magnitude to cause a current to flow between said anode and cathode terminals and through the filament of said incandescent lamp while current is flowing between said control gate and said cathode terminals and to continue the flow of current between said anode and cathode terminals and through the filament of said incandescent lamp after the flow of current between said control gate and said cathode terminals ceases whereby an illuminated indication of the operation of said control is transmitted through said cover during and after the removal of the touch of the person to said buttons.

4. A control operable to an active state in an electric circuit by the touch of a person desiring to register a signal in a control system and restorable to an inactive state in said electric circuit upon the acceptance of the registered signal by the control system comprising; a silicon controlled switch having an anode, a cathode, a control gate and an anode gate; a light transmitting cover for said switch; a button of conductive material touchable by a person and electrically connected to the control gate terminal of said switch and located on said light transmitting cover; a miniature incandescent lamp having one terminal electrically connected to the cathode terminal of said switch, said lamp being mounted behind the light transmitting portion of said cover and extending toward said button; a first parallel resistance capacitance network connected between the anode and the anode gate terminals of said switch; a first condenser connected between said button and said control gate terminal; a second condenser connected between the control gate and the cathode terminals; a first direct current source connected between said anode terminal and the second terminal of said lamp; an alternating current source connected between ground and the second terminal of said lamp having suflicient potential magnitude to cause current to flow between said control gate and said cathode terminals when said button is touched by a person; said first direct current source being of suflicient potential magnitude to cause a current to flow between said anode and cathode terminals and through the filament of said incandescent lamp while current is flowing between said control gate and said cathode terminals and to continue the flow of current between said anode and cathode terminals and through the filament of said lamp after the flow of current be tween said control gate and cathode terminals ceases, whereby an illuminated indication of the active state of said control is transmitted through said cover during and after the removal of the touch of the person to said button; a second parallel resistance capacitance network; and a second direct current source; said second direct current source being connectable between said cathode terminal and the second terminal of said incandescent lamp through said second parallel resistance capacitance network and being of a sufficient potential magnitude to stop the current flow between said anode and said cathode terminals and through the filament of said incandescent lamp when connected between said cathode terminal and the second terminal of said lamp, whereby the control is restored to an inactive state and the lamp is eX- tinguished.

References Cited by the Examiner UNITED STATES PATENTS 2,925,539 2/1960 Jellinek JOHN W. HUCKERT, Primary Examiner. J. D. CRAIG, Assistant Examiner. 

1. A CONTROL FOR ELECTRIC CIRCUITS OPERABLE BY THE TOUCH OF A PERSON AND PROVIDING AN ILLUMINATED INDICATION OF ITS OPERATED CONDITION COMPRISING; A SOLID STATE SEMICONDUCTIVE DEVICE HAVING FOUR TERMINALS INCLUDING AN ANODE TERMINAL, A CATHODE TERMINAL, AN ANODE GATE TERMINAL AND A CATHODE GATE TERMINAL; A BUTTON OF CONDUCTIVE MATERIAL CONNECTED TO SAID CATHODE GATE TERMINAL; A FIRST CURRENT SOURCE CONNECTED BETWEEN SAID ANODE TERMINAL AND SAID CATHODE TERMINAL AND APPLYING A POTENTIAL THEREACROSS; A SOURCE OF LIGHT LOCATED IN PROXIMITY WITH SAID BUTTON AND CONNECTED IN SERIES WITH SAID FIRST CURRENT SOURCE AND SAID DEVICE; MEANS CONNECTED TO SAID ANODE GATE TERMINAL FOR BIASING SAID TERMINAL WITH RESPECT TO THE POTENTIAL OF SAID ANODE TERMINAL; A PERIODIC CURRENT SOURCE CONNECTED BETWEEN GROUND AND SAID CATHODE TERMINAL, SAID PERIODIC CURRENT SOURCE HAVING SUFFICIENT POTENTIAL MAGNITUDE TO CAUSE SAID SEMICONDUCTIVE DEVICE TO CONDUCT BETWEEN SAID CATHODE TERMINAL AND SAID CATHODE GATE TERMINAL WHEN SAID BUTTON IS TOUCHED BY A PERSON; SAID FIRST CURRENT SOURCE HAVING SUFFICIENT POTENTIAL MAGNITUDE TO CAUSE SAID SEMICONDUCTIVE DEVICE TO CONDUCT BETWEEN ITS ANODE AND CATHODE TERMINALS WHEN CONDUCTION OCCURS BETWEEN ITS CATHODE AND CATHODE GATE TERMINALS AND TO CONTINUE TO CONDUCT BETWEEN SAID ANODE AND CATHODE TERMINALS AFTER CONDUCTING CEASES BETWEEN SAID CATHODE AND CATHODE GATE TERMINALS, THE CURRENT FLOWING BETWEEN SAID ANODE AND CATHODE TERMINALS WHEN CONDUCTION OCCURS THEREBETWEEN BEING SUFFICIENT TO CAUSE SAID LIGHT SOURCE TO ILLUMINATE. 